Mechanism for truing and dressing grinding wheels



April 9, 1929. I F. J. HOHNHORST 1,708,575

MECHANISM FOR TRUING AND DRESSING GRINDING WHEELS Filed Jan. 31, 1927 2 Sheets-Sheet l l I I INVENTOA.

April 1929. F. J. HOHNHORST 08,575

MECHANISM FOR TRUING AND DRESSING GRINDING WHEELS Filed Jan. 31, 1927 2 Sheets-Sheet 2 fig, 5

Patented Apr. 9, 1929.

v FERDINAND J. HOHNHORST, OF COVINGTON, KENTUCKY.

MECHANISM FOR TRUING AND DRESSING GRINDING WHEELS.

Application filed January 31, 1927. Serial No. 164,830.

The present invent-ion relates to mocha-- nism for truing and dressing grindingwheels, such as emery wheels employed in machinery for grinding or polishing surfaces of metal in precision grinding, and is exemplified as employable for truing or dressing the grinding Wheel without removing the grinding wheel from the grinding or polishing machine.

It is the object of the invention to provide novel means whereby to releasably secure my improved device with relation to the grinding wheel; further, to provide novel means employed in removing my improved device from operative relation with the grinding wheel; further, to provide novel means for causing cessation of rotation of the abrading element employed in truing or dressing the grinding wheel; further, to provide novel means for rotatively mountingv the holder for the abrading wheel further, to provide novel means wherebv to secure the rotary abrading part to itsholder and for releasing the rotary abrading part from its holder; and the invention will be further readily understood from the following de-' scription and claims, and from the drawings,

"abrading nib and the mounting therefor,

shown in a preferred relation to a grinding wheel,- the latter partly broken away.

Fig. 4 is a vertical axial section of my improved device, taken on the line 4.4 of Fig. i 3, and partly broken away.

Fig. 5 is an end elevation of my improved device, partly broken away, and viewing the interior of the chuck;

Fig. 6 is a horizontal section of my improved device taken on the'line 6-6 of Fig.

2; and, a V

"Fig. 7 is a perspective view of the releasing tool.

The invention is exemplified as employed in connection with a so-called grinding or polishing machine employing a rotary grinding wheel 11 for efiecting the grinding or polishing. i

The work to be ground or polished, which may for instance be a shaft, is arranged to be placed between suitable centers 12, 18, of

which 12 may exemplify a head'center, arranged to be rotated by suitable driving means, as by a pulley 14. A. usual quill 15 in which the head-center is supported in usual manner is journaled in a bearing 16-of the head'stock 17, slidable laterally onguid'eways 18, 19, of a table 20. j a

The tail-center 131s mounted in a suitable sleeve 21, movable axially in abearing '22 in usual manner, the bearing being on a tail-'- stock 23 laterally adjustable on the guide ways 18, 19. The table is exemplified as pivotally mounted by a pivot 25 on a saddle 26, which has lateral reciprocating motion imparted thereto by power means, in usual manner, as by a pinion 27, suitably driven, meshing with the rack 28 extending lengthwise of the saddle and fixed to the saddle. The sad; dle is slidable on guideways 29, 30, onthe frame 31 of the machine. I

The grinding wheel 11 is suitably fixed to a shaft 34, journaled in bearings 35 0f a slide 36, adjustable toward and from thework table on guideways 37, by any suitable means, the slide being arranged tobe clamped by means of suitable T-bolts and nuts 38, the" heads of the T-bolts coacting with the T-slot 39 in the frame, and the nuts clamping the slide to the frame. The shaft is rotatable in rotation of the grinding wheel for grindingor polishing straight work, or the table may be adjusted to an angle with relation to said parallelism, effected, for instance, by. rotation of the handle 12 according to the reading on the gage 13.

In the present exemplification, afreciproeating table is illustrated on which tomount the work, the grinding wheel having a sta' tionary position,.although therelation of the parts may bereversed, the Work being 'sta-j tionarlly positioned and the grinding wheel,

having reciprocations imparted to it. I have instanced the abrading part as acting on the grinding wheel in the absence of work be? The grinding machine;

tween the centers. may be of an y desirable construction.

' The rotary abrading part is exemplified an abrading nib, stub or pencil 51, herein after referred to as a nibl The abrading nib is preferably of a texture harder than the grindingwheel and of substantially smaller diameterithan the: diameter of the grinding wheel on which it operates. The abrading nib is exemplified as presented endwisel to the grinding wheelstocoact with the grinding surface of the grinding. Wheel. Itis shown I a'ibarrel 55,. shownas part of a frame 56,

whichzcomprises a base. 57, having. up-

right 58 extending, upwardly therefrom and merging into said barrel, the frame: being shown as a single casting.

Aplate 61, which I shall terman adapter I: plate,. is.--suitably secured to-the table 20, as

yimeans otfi-one-or moreT-boltsand nuts 62,

the-heads of-which: arerece'ivedwin a usual Trsloti63ain thetable 20, saidv 'boltszbeing recetved'throughholesinthe adapter plate,

the nuts beingireceived about the threaded end-of rsaid. bolts 'for: clamping the adapter plate-in adjusted: positions on the table;

The adapter plate is provided; with engagediedgess 64,: 65, at its respective edges;

' ingiithe-baseztothe'adapter plate in: suitable.

positions-"along; the adapter late; adapter; plate mayalsodae adjustabl-y secured The .baseu57 is provided with/lingers 66, which are shaped to match one oftheengaged edges-of the adapter-plate There is preferablya. pair of these fingers inseparated relation: at the respectiveends of .thebase. A clampingfinger 671coacts with theother en.-. gagedhedgeof the adapter; plate, and. is anchored ;on* a lug .68 on; the base, ton providing. a-1space69 between the clamping; finger and theerearzend ofrthebase. Aclamp bolt 70,v

shown, as provided 'with a wing, head for easy and;quicktmanipnlation, is. received through a hole in the claanpingfinger and is threaded into-azthreadedhole 71in thebase, for-clampinusuitable positions length-wise.otithe table.

The; rotatable-. abradingpart may thus be causedzto coactqvithnthe grindingnvheel at various points desired in .the lQClDI'OClIUIlQ;

travel of the table with relation to the grindingflvheela Y The .spindle54 barrel; 55 1-is provided with an internalrannular; rabbet77. Aball-bearing'TS-is located between said: enlargemenhandwthe walls of vsaidrabbet 'andv is-preferably-a radial and end thrustibearing; The innerraceway 79 OfetlHSbfill-bfllflllfi11S positioned on theene largement by the shoulder 7 6. The outer raceway "80. of said [ball-bearing is positioned in the: annual rabbet- 77, the inner end of said raeeway beingheld by theshoulder 81 forming thezinnerwall of said annular rabbet.

The i is provided with an enlarge ment i75yattl1e outer-end otwhich thereis awsh0ulder'76,:forined by the chuck 53("Tl10 A ballrbearing 85 is received between the other end-of said spindle and s'aldbarrel, and is preferably a radial and end-thrust hearing; The spindle is provideclavitli a reduced cylindrical. portion 86about which the inneiuraceway 87 ot the ball-bearing 85 isj received in suchmaniier as to perinit sliding movement between said spindle and raceway in axial directions. I

The outer raceway 88 ot the ball-bearing 85 is received in an annular rabbet 89 in the outer end 01"" thebarrehthe inward movement of'this ,latterraceway being limited by an annular. shoulder 90 forming the'inner wall ofsaid rabbet; lhe-outerrz.ceway 88 is preterably clamped .in said rabbet by a closing cap 91, which; has threaded connection with. the outer end of the barrel. his end of the spindleiis provided with a threaded shank 95. Athimble 96 provided with an inwardly extending annular flange 97 and an axial hole-98 .isreceived overthe-reduced portion 86 of the spindle, for. coaction with the inner. races way87s" A spr ng 101 1s received 111 thisthimble,

one endof the springbeing resisted by the v inwardly extending flange 97. ;An adjusts ing. nut 102- is threaded aboutthe threadedsl1.ank,.95. for adjusting the tension of the,

spring.;. This adjustingnut is provided with.

an-annular.shoulder- 103 reacting with the other end orf the'r spring and with an annular rabbet 10 1 inwhichthe outer end of thethimble 96 is received. Agclamp nut105 is threaded about the {threaded end offl the ioo spindlerfor clamping. theadjusting nut. 102;-

in adjusted position Theadjusting nut, the spring. and the ar-' rangement an d'mounting of the ball bearings provides .fora resilientv adjustable pressure upon.thewball-bearings for: maintaining. the

bitl'llSrlllPlOPBI' relations with their raceways. The shoulders 81, 90, serve as anchors to resist; approach between the raceways S0, 88 Adjustmentot. the spring; to cause greater pressure upon the spring tends to move; the I to; urge-sliding movement; lofthejspindle in the inner raceway 87 andjirto urge the ballsfof the hall bearing78 toward the inner runway 1073111the-racewaysO, 1 1

The endwise pressureupon the abradingi nibi-n-thetruing;oridressing'artion urgesend- Wise movement of the spindle toward the 1 spring: end thereof, and the spring, resists endwise vibratory movement. upon. the spin-v die; should the rotary abrading nib encounter; unevenness in the surface of: the grinding;

wheel andwhen the rotary abradinganib is ein-ployednn such .man-ner as to move part way or wholly off. the grinding' wheel inthe:

reciprocating movements between the rotary abrading nib and the grinding wheel during the truing or dressing operations.

The cap 91 is shown of cup shape to enclose the outer end of the spindle, the spring and its adjusting parts. There is a space indicated generally at 108extending through out the cap and the barrel'and between the balls and raceways of the ball-bearings, forming a lubricant space which may be filled with lubricant, for instance a heavy oil, so that all moving parts in the barrel maybe thoroughly lubricated. The lubricant may be supplied through a usual lubricant nipple 109 secured to the cap, as by athreaded connection, and communicating with said space. A washer 110, which may be'of absorbent material, is located between the chuck 53 and the adjacent end of the barrel.

The rotary abrading part, exemplified as the nib, is normally quiescent. Rotation is imparted to the abrading nib by contact with the rotating grinding wheel. The abrading nib is presented toward the grinding wheel in such relation asto cause coaction between the abrading nib at one side of its axis of rotation and the rotating grinding wheel.

For effecting this contact and rotation, the rotary abrading nib is preferably presented with its axis of rotation at an angle at a plane perpendicular to the axis of rotation of the grinding Wheel. The axis of rotation ofthe abrading nib may also be presented'in a line which is slightly tangent to a circle whose center is coincident with the axis of rotation of the grinding wheel, exemplified by theupward slant of the abrading nib toward the grinding wheel in Fig. 2. The angles of the axis of rotation of the rotary abrading nib stated are preferably slight, being in prac-' tice about five degrees, although these angles may be more or less, depending on the fineness or coarseness with which the truing or dressing operation isto be performed. The

greaterthat this angle of presentation is, the

coarser will be the action upon the grinding wheel, and the more nearly the axis of rotation of the rotary abrading part approaches a line which is radial in a plane perpendicular to the axis of rotation of the grinding wheel, the finer will be the resultant effect upon the grinding surface of the grinding wheel. The endwise presented rotary abradingnib acts with a swirling motion upon the grinding surface of the grinding wheel.

The rotary abrading nib is preferably provided with an axial bore, so as to avoid the formation of a hump or point of resistance of abrading material atand immediately adjacent to theaxis of rotation of the rotary abrading part, thereby avoiding streaks or scars or marring of the grinding surface of the grinding wheel, and insuring accurate truing and dressing of said grinding surface.

The body of th1s nib is preferably formed- .of closely united and hard abrading material which is not readilymachined, but may be of other structure, and is provided'with ashank 115, about which there is a collar 116 of machinable material, for instance Babbittmetal, which is poured or molded about the shank so as to have fixed relation thereto and to form a. stem, by means of whi-ch the nib may be readily held in the chuck.

' The means for securing the nib in the chuck are in the present exemplification shown as comprising asocket 118 in thechuck, which has an inwardly contracting tapering wall, the outer periphery of the collar 116 about the shank being 1 provided with r a I similarly tapered outer periphery, which is. complemental to the inner tapered wall of the socket of the chuck, for forming intimate connection therewith, and for clampingly holding the abrading nib in the chuck. When the abrading nib isfirmlyseatedin the chuck there is still preferably an annular space 119 between the annular shoulder 120 at the inner end of the rotary'nib and the outer end of the wall of the socket of the chuck.

' In order to provide maintenance of rotation of the rotary abrading part and smoothness of operation and accurate work between it and the grinding surface of the grinding wheel, a flywheel effect is provided for the chuck, instanced as an enlargement of the chuck, as by providing a fly-wheel collar 121 for the chuck. This collar has a rearward annular extension 122 received about the stationary tubular end 123 of the barrel 55 and the bearing 78 in said barrel. This tubular end may be providecl with an annular groove 1% for oil or as an air cushion.

The collar is received about thechuck an( is rigidly secured thereto. 1 This is effected by providing the collar wit-han internal slightly inwardly tapered bore 125, preferably terminating at a shoulder 126, and by providing the outer face of the chuck with'a complemental tapered outer periphery 127. The collar is received about the chuck and the chuck firmly wedged therein to form a rigid structure. i v Means are provided for readily releasing the rotary abrading nib'froni' its chuck, instanced as accomplished byan extractor plate 131,provided with a central threaded bore 132. An extractor bolt 133' is threaded in said bore, and is arrangedto be'resisted by the inner wall 134 of the chuck socket. 'The extractor plate is axially movable in the inner socket portion 135' 'of-the chuck, which is preferably cylindrical. The ex tractor bolt is provided with asocket 136, which is formed in cross-section so as to receive and be turned by a suitable tool, exemplified at 137. The coacting faces of the wrench and socket 136 are shown polygonal in cross-section, The shank of the wrench is received through the bore 52 in the abrading llibl'l ffil" coacitionawith the extractor bolt, and thewextractor bolt, isi-tua'ned ;with relation: to

the extractor plate, for: moving the extractor plate away from'thezbottom of the socket, for exerting extracting force. upon the abrading nib in the socket, for removing the abrading" through holes. in the extractor. plate: and

threadedvinc the bottom-of thetsocket of the chuck, these retaining-screwsbeing provided with" heads-* normally received: in 1 enlargementsrl ifliof the holes in the extractor plate.

1 The combined chuck and fiyswheel is preferably provided with radial 'iholes -143,.-for receivingga suitable spanner wrench, for holding-the chuck against-rotation: during rotation of atheuextractorrboltformoving the extractor plate; a a

Itis found dcsirablein practice to move the abradingmechanism from the grinding machine and to attach the same thereto.

is desired, to causethe 'removal immediately a on: cessation-of dressing action of the nib. T lie-nib is caused to-rotate at high speed by its coactionwith the grinding'wheelyand the fly-wheel effect uponithe rotary n-ibis such, 1 that itwouldordinarilycontinue its rotations for acomparatively.longperiod of. time. It is' desirable howeverthat rotations: of the ro= tary nib shall cease promptly so as to provide ease, promptness' and safetyxfor the-handling of the abradingmachine; Novel means are therefore provided for-such removal and attaehment, and li'fting'rmeansare provided for the abradi-ng machine which coact with a abrake forzcansing 'cessation of'rotationoof the abrading nib and chuck.- V a A handle 151 .is onalever-152 pivotediat 153- to lugs-154 extending upwardly from: the

barrel 55, and having an arm 155 extendingaboi e the fly-wheel 121.7 Abrake-shoe'156,

shown as a plugreceived in a: socket 157 in the arm 155, is arranged to. coact'with the chuck orfly-wheel thereof, for arrestinggrotation of the samewhen the handle 151;is:-grasped to raise the abradingmachine; JW'hen the abrading machineisraisedor carried by the handle, the weight of the abradingtmachine acts on the brake-shoe for' braking action" uponthe abrading nib, its chuck and fly wheel, The parts and mounting thereof are so relatedthat the lever 152fis normally'overweighted'at' itshandle end for normally causing separation :betweenthe brake shoe and clutch and fly wheelthereofl The arm I I 155 is provided with ahole158 through which 7 It ,is also desirable in practice where such removal" shown and described are not herein claimed, 7

the same being fully shown, described and claimedin a copending application, CllVI- sionalhereof', forUnited States patent on improvements in mechanism for truing and dressing Having thus fully described my invention,

whatI'cla-im as new, and desire to secure by- Letters Patent, is

1. In an abrading machine for grinding wheels, the combination of'a frame,'a rotary grinding wheel's, Serial No. 314,141, filed October22, 1928.

abrading part rotatable-on said fran1e,'a

brake. for said rotary abrading part, and a lifting handle for said machine acting by lifting movement" thereof to apply said brake.

2; In an abrading machine for grinding wheels,thecombination of a frame, a rotary abradmg part rotatable'on said frame, a

brake for said rotary abrading part, and a lifting handle for the machine acting by lifting movement thereof to apply said'bra'ke, said lifting handle normally in brake release relation.

'3, In an abrading machine for grinding wheels, the combination of a frame,'a rotary abrading'part rotatable on said frame, a brake for said rotary abrading-part, and a lifting handle for the machine, said lifting handle having operative connection with said brake for applying said brake by the weight of the machine suspended by said handle. 7 1 7 4. In -an abrading machine for grinding wheels, thecombination ofa frame, a rotary abrading part rotatable on 'said frame,'a brake for sald rotary abrading part, and a liftinghandle pivoted to said frame, said lifting: handle having operative connection with said brake for applying said brake by gravity Weight o'f'the machinesuspended by said handle-during lifting action thereon;

said handle being normally in brake releasing. relation. i 1

5.- In an abrading machine for grinding wheels, the combination of a framefa'rotary abrading part rotatable onsaid frame, a brakeforsaid rotary abrading part,and a liftinghandle on said frame in such relation thatlifting actionupon said handle, causes braking actionuof said brake and releasing of said handle causes release of said brake; H

6. Inan abrading machine for grinding wheels, the combination of a frame, aspi'ndle Journaled 1n said'frame, a chuck structure fora rota-table abrading nibon said spindle,

a lifting lever-pivoted to said frame,and a Wheel, the combination of a frame, a spindle, a chuck structure at one end of said spindle for a rotary abrading nib, spaeed-apart bearings for said spindle at one side of said chuck structure, a lifting handle pivoted to said frame adjacent to said chuck structure and one of said bearings, and a brake on said lifting handle arranged to coact with said chuck structure by lifting movement of said handle.

8. In an abrading machine for a grinding Wheel, the combination of a frame comprising a barrel, a bearing at each end of said barrel, a spindle journaled in said bearings, a chuck structure at one end of said spindle comprising an end socket for reception of a rotary abrading nib and an annular apron about the end of said barrel adjacent to said chuck structure, a lifting lever having pivotal connection with said barrel adjacent to said chuck structure, said lifting lever comprising a lifting handle at one end, and a brake for said chuck structure at its other end, With said brake normally in release relation, and arranged for being shifted into brake relation with saidchuek structure by lifting of said handle.

In testimony whereof, I have hereunto signed my name.

FERDINAND J. HOHNHORST. 

